803 vs 948 Confusion persists.

[rogerowen]

In my bid to replace an 803 with a 948, I learn that the carburettor is a different size - although the manifold on each appears to be the same (photo of 803). Should I be looking to find an HS2 and manifold from a 1098? or will I be able to fit an HS2 onto this older type of manifold?[frame][/frame]

[mike.perry]

The 803 carb is an H1 11/8in, the 948 carb is an H2 or HS2 11/4in. I think that the mounting stud spacings are different. You would be much better getting a 1098 manifold.

[brucek]

The carb-inlet manifold shape is also different on the 948/1098. The 948/1098 is diamond shaped with rounded ends, the 803 is as you see in the photo a bit squarer. There are plenty of later manifolds around so finding one shouldn't be a problem.

[rogerowen]

Hmmm. Here's a picture of the manifold fitted to the 948 lump. Looks just like the 803 one to me - hence my confusion.[frame][/frame]

[bmcecosse]

NO - that 948 manifold is NOT like the 803 one.. It can be used - but the later HS2 manifold is better.

[brucek]

Absolutely. It's the joint between the carb and inlet manifold that is different . Your 803 picture shows the carb and spacer block which is clearly a different shape to the carb mount on the 948 manifold in the later photo. The rest of the manifold is the same I think. By choice, the later 1098 one is a better unit, is as cheap as chips and is readily available.

[mike.perry]

If in doubt - Try it out

[rogerowen]

'Should have gone to Spec-Savers'. I think I can see what you say. Next Question.... what carb would have been fitted originally to the 948?

[PSL184]

Hs2

[mike.perry]

See my earlier reply, 1956-9 H2, 1959-62 HS2

[rogerowen]

OK, thanks!

[rogerowen]

Ah!, If there was a change in carburettors from H2 to HS2 on the 948, could this explain the different manifolds between early and late 948's? I have another 948 engined car (1960) and the manifold arrangement is completely different to the 948 engine I intend to replace the 803 car.[frame][/frame]